There are many highly accurate techniques for diagnosing disorders of the brain and nervous system. Unfortunately, many of them require large and immovable equipment, extremely sophisticated computers, and highly trained personnel to operate them. They are not suitable for first responders, paramedics and other field medical personnel. They also are not suitable for the rapid use that medical emergencies require. Similarly, they often are not suitable for use in surgical suites where working room is at a premium, and the large electromagnetic fields generated by some types of equipment are not compatible with other equipment, tools, and personnel typically present.